Generally, information transceived between transmitting and receiving sides in a communication system is classified into control information and data information. The data information means user data corresponding to payload, whereas the control information means such information for transceiving data information on a transport channel as system configuration, a modulation scheme, a coding scheme and the like. In order to efficiently use limited radio resources, the control information is configured to have a minimum length in general and undergoes a coding scheme that is strong against error on a radio channel due to its influence on system performance.
Coding schemes can be categorized into a blocking scheme, a convolutional coding scheme and a turbo coding scheme. In the block coding scheme, an input sequence is coded once by a block unit without using a memory. Unlike the convolutional coding scheme, this means that a generated codeword has not a variable length but a fixed codeword length. Widely used codes include Hamming code, RS (Reed-Solomon) code and RM (Reed Muller) code for example.
The convolutional coding scheme uses a shift register as a sort of memory and is mainly used for coding of speech data. The turbo coding scheme performs coding by a combination means of a recursive systematic convolutional (RSC) coder, interleaving and iterative decoding and is mainly used in coding not speech data but user data.
In the above-described coding schemes, regarding contents of input data to be coded, a presence or non-presence of iterative permissibility of input data transfer, transfer delay sensitivity, significance of transmission contents and the like, which one of the coding schemes will be used is determined according to what kind of level of a reception signal quality is required.
In 3GPP (3rd generation partnership project: standardization organization of 3rd generation mobile communication system) mobile communication system, as a coding scheme for control information, a short-length block coding scheme based on RM coding, a tail-biting convolutional coding scheme, a simplex coded iterative coding scheme or the like is used.
In the above-described coding schemes, which coding scheme will be applied is determined according to a reception signal quality (target quality) requested by the above-transmitted control information in a receiving side. Generally, control informations coded by a specific coding scheme are requested to meet the same signal quality (e.g., block error rate, etc.).